School me on center counter weighted cranks

So I see more and more engines being built with "center" counter weighted cranks.

Is this somthing I should consider for a new build?

The smart people like them. That's good enough for me to want one.

Ford stock 2011/19 5.0 cw cranks are sold as thier performance crank. Never had a failure!
I run one from Crower in my 528. No cap walk anymore. They take the extra loads off 2& #4 bearings caus e d by non cw cranks, and put it on #3 where it belongs. Would reduce flexing of the crank also, adding to crank life.

The theory is sound, but the practical aspect?
IIRC CCW cranks were used in 392 fuel engines back when, no improvement (Gene Adams). Perhaps this crank is inherently stiffer than current big blocks due to shorter OAL?

I use a Molnar non center ounter weight crank. No issues at 900?+. Sure a center counter weighted would be nice Try and purchase one for $900. Do you want it, sure. Do you need it? More than likely not.
Doug

Adding pounds to you rotating mass isn't going to help the goal of faster...unless either your power is so high or the stability of your crank so low you have to have it. Agreed that sharing the weight mass of 2 through the center of the crank is stressful without them. Why carry them down the track, or have to accelerate them on every shift if you aren't overloading the crank?

There's a reason a PS crank weighs close to 35 pounds.

The practical reasons for a ccw crank are better stock block life, and ultimate life of the crank. Also helping reduce or eliminate cap walk in my Megablock. Most racers won't really need one. But the advantages are there or Ford wouldn't use them in all 11 to 19 year 5.0 Mustang motors. Also as i said earlier , they sell that stock crank as thier performance part, zero failures. Some of those race turbo motors i assume are putting out some serious hp!

So they are heavier? Aren't all the current SS/AH engines center weighted? Are LS engines stock from the factory this way?

Don't forget about additional windage too. I'm all for them when they're required, but that has a lot to do with parts quality, and application to me. A ccw eagle crank would be more damaging than an no ccw bryant for the same application. Comes down to rigidity

Winberg makes cranks for all classes of drag racing and most other forms of racing.

I can't find a photo of one of their cranks that do not have center counter weights.

The attached photo is of some of their top fuel crankshafts.

The cap walk disappears with the CCW crankshaft. They are around 10#'s heavier depending on the manufacturer. Both of mine are over 80#'s.

I'm putting another pump gas 400 stock 4.250 stroke block stroker motor that has a Windberg crank with billet steel Crower rods I bought used from a member back east several years back, it doesn't have the center counter weights
I do have two fully counterweighted older top fuel or blown alcohol cranks, one is a Bryant that was 4.25 stroke with Mopar rod size(now offset ground down to BB Chevy size with 4.375 stroke) and the other is a older KB 4.500 stroke that was cracked in four places that I had fix with Mopar rod size, it couldn't be offset stroked though
I'm planning on using both of those cranks in after market blocks to help prevent cap walk and see if I can exceed 1000 HP + N/A

Strictly speaking, for greatest control of out-of-balance forces, the counterweights should be moved inboard touching the cheek radius, and made as thin as possible to concentrate inertia as close directly opposite (180°, at the smallest diagonal) to the pins as possible, with the OD increased as needed to get the correct mass back. Any late weight adjustments (holes, Mallory) should be limited to the shallowest correction to the inner face of the CW only.
Not practical.
This is true (and nearly impossible) even for the "inherently perfectly balanced" L6 engines as well.

Note that the Winbergs shown are directionally biased for rotation...

So, is a center counterweighted crank an improvement or not?

Yes, but it's:
1. expensive
2. not magic - your power level and specific engine design may make it a conversation piece

You would also be faster if you center-drilled every fastener, like they did with Moto-X in the 1970s. 10 hours of labor to save 1 lb.

Expanding on my prior post: given a clean sheet of paper, a "V" engine can, and has been built with separate crank-pins at the same position (G.M.C. 301 etc. V6), which would allow a counterweight between them. But if you don't need it, it's just one more thing for the engineers to argue with the accountants...

https://www.dragzine.com/news/crank-balancing-weight-options-from-callies/


https://vimeo.com/252601712

Higher rpm engines seem to like CCW cranks. The weight becomes rotating inertia...not a bad thing.

Ideally, every mass would be opposed by a counterweight placed exactly opposite: 180° away. This is not possible since the pistons occupy that space.
Any compensating mass NOT correctly placed (alongside, diagonal, etc.) has the effect of forming a bending plane with its axis a line through both centers of mass - a diagonal angled away from the crank's axis of rotation. The greater the misalignment, higher RPM, and greater mass the stronger the bending force. Bad.

Years ago I saw some SB Chevy NASCAR cranks at ABS in L.A area, they where super light weight,33 lbs., and the counter weights where offset to help longevity for high RPM according to the owner of ABS
They where very pretty

So, does that mean CCW cranks do or don't reduce cap walk?

I see i've exceeded the audience's attention span... again.
I'll try to use more slang and fewer facts in future.

the counter weights where offset to help longevity for high RPM
I leave mine home to save weight.

Why is expensive Mallory weight always added to a crankshaft counterweight? Why couldn't the underside of a piston or the bottom of a rod cap be lightened instead? The trick is to keep it as light as possible, isn't it? Why keep adding weight? I see this on tires in the dealership. People that have had their tires balanced several times in their life. Some come in with weights all over the inside of the rim. We all know that this is laziness on the part of the tech balancing the tires. Can the same be said for crank balancing?

If you are adding weight to a counter weight, it's because it's too light. You can't take that much out of a rod cap or a piston unless the piston is junk. Let's say all you need is 15-20 grams of Mallory. You ain't going to find that much weight to remove between the rods and the Pistons unless they are just flat out garbage.

Maybe less emphasis of your college degree would be more helpful.... if you actually do have an understanding of that which you speak.

long on words indicates a shortage of understanding.

What a rude little boy you are. You asked the same question several times, but are unable to understand that there is no definitive answer: you're responsible for your own decisions.
Which "college degree" are you referring to?
Incomplete comprehension indicates a shortage of intelligence.

But the same 15-20 grams split between 8 pistons and 8 rods might be doable. Does anyone actually know the relationship between rod/piston weight relative to where 1 weight is added to a crankshaft?

For this method, in a V8 with 90° bank angle, the relationship: balance weight = 100% of rotating mass + 50% of reciprocating mass. Other engines vary all over the map.

Not that easy.
A connecting rod has, by popular convention, its weight divided into reciprocating (top) and rotating (bottom) components. The line of division is the center of gravity.
Missing from this equation: a really long rod (3:1 ratio) has most of its reciprocating thrust in the vertical plane, a short rod (1.3:1) has a far larger horizontal component.
Conventional balancing completely ignores this (but it's critical to motorcycle engines).

Son, Incomprehensive explanation indicates a shortage of intelligence.

You didn't find a complete answer to your question in my statement?
Not my job.

Man, I hate it when it's cold outside. Everybody gets all testy lol.

The long and short of it is this. You typically only find center weights on expensive cranks, designed by smart folks. Bryant, and winberg to me are top of the heap of the stuff we all use. They have suggested them for one application, and recommended against in others. So if you're wondering how to order your 3 to 5 thousand dollar crank, either of those shops will shoot you straight without any regard for making more money. A benefit of dealing with top, established shops that really care about reputation, and quality.

I can answer that question .................

Which "college degree" are you referring to? - "I’m entirely self-taught, and have no professional engineering or technical training."

Translation: "I didn't sit in a room while someone read prepared text to me until I could repeat it".
Anyone have a different description for a degree? Hint: none of them involve getting under a car, do they?

Thanks Dt Hemi for some real world insight on a interesting subject

That sounds exactly like some of the electrical engineers I had to deal with while working for the telephone company that knew nothing about customer service or dealing with them

UGH...Never gonna understand why some folks get so butthurt over some of this stuff.

As for the question at hand. A center counter weighted crank is always better IF it is needed for your application..

So what would be the applications for a Center counter weighted crank?

high rpm, high HP, to save/add life to a stock block.

$3000 crank in a stock block? Seems backwards to me.
Doug

Doug,after cracking one $800 crank in 100 runs, and chewing up the maincaps in my nice new megablock back in 05, i spent 2300 for a Crower ccw. I figure guys that are somewhat commited to stock blocks might find it and reasonable alternative if it doubles or triples the life of thier block. A busted block also means a lost race and or weekend, all that machinework and parts, and block cores that are getting tougher to find.